I have following concept that I’d like to use, but I cant find any hints about it (maybe I can’t come up with good search phrase).
On this quick sketch you can see two objects and a hole (red).
Idea is - violet object gets thrown in the hole and disappears - green lines indicate where it should be visible, but it’s not.
Everything behind is perfectly visible (blue cube).
Best what I came up is editing mesh on the fly on hole-object intersection.
Maybe someone has better idea? Preferably - doable in Unity Free.
There are several forum threads about this so, yes portal like teleportations are possible in Unity. As there is another forum about it, it all depends on your skill with manipulating what Unity gives you.
Doesn’t really sound like you’re after “Portal” type functionality. First thing I thought of when I saw your sample image was one of the Vectrosity samples, so maybe take a look at that and see if it helps.